1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.hardware;
18
19import android.os.Looper;
20import android.os.Process;
21import android.os.RemoteException;
22import android.os.Handler;
23import android.os.Message;
24import android.os.ServiceManager;
25import android.util.Log;
26import android.util.SparseArray;
27import android.util.SparseBooleanArray;
28import android.util.SparseIntArray;
29import android.view.IRotationWatcher;
30import android.view.IWindowManager;
31import android.view.Surface;
32
33import java.util.ArrayList;
34import java.util.Collections;
35import java.util.HashMap;
36import java.util.List;
37
38/**
39 * <p>
40 * SensorManager lets you access the device's {@link android.hardware.Sensor
41 * sensors}. Get an instance of this class by calling
42 * {@link android.content.Context#getSystemService(java.lang.String)
43 * Context.getSystemService()} with the argument
44 * {@link android.content.Context#SENSOR_SERVICE}.
45 * </p>
46 * <p>
47 * Always make sure to disable sensors you don't need, especially when your
48 * activity is paused. Failing to do so can drain the battery in just a few
49 * hours. Note that the system will <i>not</i> disable sensors automatically when
50 * the screen turns off.
51 * </p>
52 *
53 * <pre class="prettyprint">
54 * public class SensorActivity extends Activity, implements SensorEventListener {
55 *     private final SensorManager mSensorManager;
56 *     private final Sensor mAccelerometer;
57 *
58 *     public SensorActivity() {
59 *         mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
60 *         mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
61 *     }
62 *
63 *     protected void onResume() {
64 *         super.onResume();
65 *         mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
66 *     }
67 *
68 *     protected void onPause() {
69 *         super.onPause();
70 *         mSensorManager.unregisterListener(this);
71 *     }
72 *
73 *     public void onAccuracyChanged(Sensor sensor, int accuracy) {
74 *     }
75 *
76 *     public void onSensorChanged(SensorEvent event) {
77 *     }
78 * }
79 * </pre>
80 *
81 * @see SensorEventListener
82 * @see SensorEvent
83 * @see Sensor
84 *
85 */
86public class SensorManager
87{
88    private static final String TAG = "SensorManager";
89    private static final float[] mTempMatrix = new float[16];
90
91    /* NOTE: sensor IDs must be a power of 2 */
92
93    /**
94     * A constant describing an orientation sensor. See
95     * {@link android.hardware.SensorListener SensorListener} for more details.
96     *
97     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
98     */
99    @Deprecated
100    public static final int SENSOR_ORIENTATION = 1 << 0;
101
102    /**
103     * A constant describing an accelerometer. See
104     * {@link android.hardware.SensorListener SensorListener} for more details.
105     *
106     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
107     */
108    @Deprecated
109    public static final int SENSOR_ACCELEROMETER = 1 << 1;
110
111    /**
112     * A constant describing a temperature sensor See
113     * {@link android.hardware.SensorListener SensorListener} for more details.
114     *
115     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
116     */
117    @Deprecated
118    public static final int SENSOR_TEMPERATURE = 1 << 2;
119
120    /**
121     * A constant describing a magnetic sensor See
122     * {@link android.hardware.SensorListener SensorListener} for more details.
123     *
124     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
125     */
126    @Deprecated
127    public static final int SENSOR_MAGNETIC_FIELD = 1 << 3;
128
129    /**
130     * A constant describing an ambient light sensor See
131     * {@link android.hardware.SensorListener SensorListener} for more details.
132     *
133     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
134     */
135    @Deprecated
136    public static final int SENSOR_LIGHT = 1 << 4;
137
138    /**
139     * A constant describing a proximity sensor See
140     * {@link android.hardware.SensorListener SensorListener} for more details.
141     *
142     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
143     */
144    @Deprecated
145    public static final int SENSOR_PROXIMITY = 1 << 5;
146
147    /**
148     * A constant describing a Tricorder See
149     * {@link android.hardware.SensorListener SensorListener} for more details.
150     *
151     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
152     */
153    @Deprecated
154    public static final int SENSOR_TRICORDER = 1 << 6;
155
156    /**
157     * A constant describing an orientation sensor. See
158     * {@link android.hardware.SensorListener SensorListener} for more details.
159     *
160     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
161     */
162    @Deprecated
163    public static final int SENSOR_ORIENTATION_RAW = 1 << 7;
164
165    /**
166     * A constant that includes all sensors
167     *
168     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
169     */
170    @Deprecated
171    public static final int SENSOR_ALL = 0x7F;
172
173    /**
174     * Smallest sensor ID
175     *
176     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
177     */
178    @Deprecated
179    public static final int SENSOR_MIN = SENSOR_ORIENTATION;
180
181    /**
182     * Largest sensor ID
183     *
184     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
185     */
186    @Deprecated
187    public static final int SENSOR_MAX = ((SENSOR_ALL + 1)>>1);
188
189
190    /**
191     * Index of the X value in the array returned by
192     * {@link android.hardware.SensorListener#onSensorChanged}
193     *
194     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
195     */
196    @Deprecated
197    public static final int DATA_X = 0;
198
199    /**
200     * Index of the Y value in the array returned by
201     * {@link android.hardware.SensorListener#onSensorChanged}
202     *
203     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
204     */
205    @Deprecated
206    public static final int DATA_Y = 1;
207
208    /**
209     * Index of the Z value in the array returned by
210     * {@link android.hardware.SensorListener#onSensorChanged}
211     *
212     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
213     */
214    @Deprecated
215    public static final int DATA_Z = 2;
216
217    /**
218     * Offset to the untransformed values in the array returned by
219     * {@link android.hardware.SensorListener#onSensorChanged}
220     *
221     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
222     */
223    @Deprecated
224    public static final int RAW_DATA_INDEX = 3;
225
226    /**
227     * Index of the untransformed X value in the array returned by
228     * {@link android.hardware.SensorListener#onSensorChanged}
229     *
230     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
231     */
232    @Deprecated
233    public static final int RAW_DATA_X = 3;
234
235    /**
236     * Index of the untransformed Y value in the array returned by
237     * {@link android.hardware.SensorListener#onSensorChanged}
238     *
239     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
240     */
241    @Deprecated
242    public static final int RAW_DATA_Y = 4;
243
244    /**
245     * Index of the untransformed Z value in the array returned by
246     * {@link android.hardware.SensorListener#onSensorChanged}
247     *
248     * @deprecated use {@link android.hardware.Sensor Sensor} instead.
249     */
250    @Deprecated
251    public static final int RAW_DATA_Z = 5;
252
253    /** Standard gravity (g) on Earth. This value is equivalent to 1G */
254    public static final float STANDARD_GRAVITY = 9.80665f;
255
256    /** Sun's gravity in SI units (m/s^2) */
257    public static final float GRAVITY_SUN             = 275.0f;
258    /** Mercury's gravity in SI units (m/s^2) */
259    public static final float GRAVITY_MERCURY         = 3.70f;
260    /** Venus' gravity in SI units (m/s^2) */
261    public static final float GRAVITY_VENUS           = 8.87f;
262    /** Earth's gravity in SI units (m/s^2) */
263    public static final float GRAVITY_EARTH           = 9.80665f;
264    /** The Moon's gravity in SI units (m/s^2) */
265    public static final float GRAVITY_MOON            = 1.6f;
266    /** Mars' gravity in SI units (m/s^2) */
267    public static final float GRAVITY_MARS            = 3.71f;
268    /** Jupiter's gravity in SI units (m/s^2) */
269    public static final float GRAVITY_JUPITER         = 23.12f;
270    /** Saturn's gravity in SI units (m/s^2) */
271    public static final float GRAVITY_SATURN          = 8.96f;
272    /** Uranus' gravity in SI units (m/s^2) */
273    public static final float GRAVITY_URANUS          = 8.69f;
274    /** Neptune's gravity in SI units (m/s^2) */
275    public static final float GRAVITY_NEPTUNE         = 11.0f;
276    /** Pluto's gravity in SI units (m/s^2) */
277    public static final float GRAVITY_PLUTO           = 0.6f;
278    /** Gravity (estimate) on the first Death Star in Empire units (m/s^2) */
279    public static final float GRAVITY_DEATH_STAR_I    = 0.000000353036145f;
280    /** Gravity on the island */
281    public static final float GRAVITY_THE_ISLAND      = 4.815162342f;
282
283
284    /** Maximum magnetic field on Earth's surface */
285    public static final float MAGNETIC_FIELD_EARTH_MAX = 60.0f;
286    /** Minimum magnetic field on Earth's surface */
287    public static final float MAGNETIC_FIELD_EARTH_MIN = 30.0f;
288
289
290    /** Standard atmosphere, or average sea-level pressure in hPa (millibar) */
291    public static final float PRESSURE_STANDARD_ATMOSPHERE = 1013.25f;
292
293
294    /** Maximum luminance of sunlight in lux */
295    public static final float LIGHT_SUNLIGHT_MAX = 120000.0f;
296    /** luminance of sunlight in lux */
297    public static final float LIGHT_SUNLIGHT     = 110000.0f;
298    /** luminance in shade in lux */
299    public static final float LIGHT_SHADE        = 20000.0f;
300    /** luminance under an overcast sky in lux */
301    public static final float LIGHT_OVERCAST     = 10000.0f;
302    /** luminance at sunrise in lux */
303    public static final float LIGHT_SUNRISE      = 400.0f;
304    /** luminance under a cloudy sky in lux */
305    public static final float LIGHT_CLOUDY       = 100.0f;
306    /** luminance at night with full moon in lux */
307    public static final float LIGHT_FULLMOON     = 0.25f;
308    /** luminance at night with no moon in lux*/
309    public static final float LIGHT_NO_MOON      = 0.001f;
310
311
312    /** get sensor data as fast as possible */
313    public static final int SENSOR_DELAY_FASTEST = 0;
314    /** rate suitable for games */
315    public static final int SENSOR_DELAY_GAME = 1;
316    /** rate suitable for the user interface  */
317    public static final int SENSOR_DELAY_UI = 2;
318    /** rate (default) suitable for screen orientation changes */
319    public static final int SENSOR_DELAY_NORMAL = 3;
320
321
322    /**
323     * The values returned by this sensor cannot be trusted, calibration is
324     * needed or the environment doesn't allow readings
325     */
326    public static final int SENSOR_STATUS_UNRELIABLE = 0;
327
328    /**
329     * This sensor is reporting data with low accuracy, calibration with the
330     * environment is needed
331     */
332    public static final int SENSOR_STATUS_ACCURACY_LOW = 1;
333
334    /**
335     * This sensor is reporting data with an average level of accuracy,
336     * calibration with the environment may improve the readings
337     */
338    public static final int SENSOR_STATUS_ACCURACY_MEDIUM = 2;
339
340    /** This sensor is reporting data with maximum accuracy */
341    public static final int SENSOR_STATUS_ACCURACY_HIGH = 3;
342
343    /** see {@link #remapCoordinateSystem} */
344    public static final int AXIS_X = 1;
345    /** see {@link #remapCoordinateSystem} */
346    public static final int AXIS_Y = 2;
347    /** see {@link #remapCoordinateSystem} */
348    public static final int AXIS_Z = 3;
349    /** see {@link #remapCoordinateSystem} */
350    public static final int AXIS_MINUS_X = AXIS_X | 0x80;
351    /** see {@link #remapCoordinateSystem} */
352    public static final int AXIS_MINUS_Y = AXIS_Y | 0x80;
353    /** see {@link #remapCoordinateSystem} */
354    public static final int AXIS_MINUS_Z = AXIS_Z | 0x80;
355
356    /*-----------------------------------------------------------------------*/
357
358    Looper mMainLooper;
359    @SuppressWarnings("deprecation")
360    private HashMap<SensorListener, LegacyListener> mLegacyListenersMap =
361        new HashMap<SensorListener, LegacyListener>();
362
363    /*-----------------------------------------------------------------------*/
364
365    private static final int SENSOR_DISABLE = -1;
366    private static boolean sSensorModuleInitialized = false;
367    private static ArrayList<Sensor> sFullSensorsList = new ArrayList<Sensor>();
368    private static SparseArray<List<Sensor>> sSensorListByType = new SparseArray<List<Sensor>>();
369    private static IWindowManager sWindowManager;
370    private static int sRotation = Surface.ROTATION_0;
371    /* The thread and the sensor list are global to the process
372     * but the actual thread is spawned on demand */
373    private static SensorThread sSensorThread;
374    private static int sQueue;
375
376    // Used within this module from outside SensorManager, don't make private
377    static SparseArray<Sensor> sHandleToSensor = new SparseArray<Sensor>();
378    static final ArrayList<ListenerDelegate> sListeners =
379        new ArrayList<ListenerDelegate>();
380
381    /*-----------------------------------------------------------------------*/
382
383    private class SensorEventPool {
384        private final int mPoolSize;
385        private final SensorEvent mPool[];
386        private int mNumItemsInPool;
387
388        private SensorEvent createSensorEvent() {
389            // maximal size for all legacy events is 3
390            return new SensorEvent(3);
391        }
392
393        SensorEventPool(int poolSize) {
394            mPoolSize = poolSize;
395            mNumItemsInPool = poolSize;
396            mPool = new SensorEvent[poolSize];
397        }
398
399        SensorEvent getFromPool() {
400            SensorEvent t = null;
401            synchronized (this) {
402                if (mNumItemsInPool > 0) {
403                    // remove the "top" item from the pool
404                    final int index = mPoolSize - mNumItemsInPool;
405                    t = mPool[index];
406                    mPool[index] = null;
407                    mNumItemsInPool--;
408                }
409            }
410            if (t == null) {
411                // the pool was empty or this item was removed from the pool for
412                // the first time. In any case, we need to create a new item.
413                t = createSensorEvent();
414            }
415            return t;
416        }
417
418        void returnToPool(SensorEvent t) {
419            synchronized (this) {
420                // is there space left in the pool?
421                if (mNumItemsInPool < mPoolSize) {
422                    // if so, return the item to the pool
423                    mNumItemsInPool++;
424                    final int index = mPoolSize - mNumItemsInPool;
425                    mPool[index] = t;
426                }
427            }
428        }
429    }
430
431    private static SensorEventPool sPool;
432
433    /*-----------------------------------------------------------------------*/
434
435    static private class SensorThread {
436
437        Thread mThread;
438        boolean mSensorsReady;
439
440        SensorThread() {
441        }
442
443        @Override
444        protected void finalize() {
445        }
446
447        // must be called with sListeners lock
448        boolean startLocked() {
449            try {
450                if (mThread == null) {
451                    mSensorsReady = false;
452                    SensorThreadRunnable runnable = new SensorThreadRunnable();
453                    Thread thread = new Thread(runnable, SensorThread.class.getName());
454                    thread.start();
455                    synchronized (runnable) {
456                        while (mSensorsReady == false) {
457                            runnable.wait();
458                        }
459                    }
460                    mThread = thread;
461                }
462            } catch (InterruptedException e) {
463            }
464            return mThread == null ? false : true;
465        }
466
467        private class SensorThreadRunnable implements Runnable {
468            SensorThreadRunnable() {
469            }
470
471            private boolean open() {
472                // NOTE: this cannot synchronize on sListeners, since
473                // it's held in the main thread at least until we
474                // return from here.
475                sQueue = sensors_create_queue();
476                return true;
477            }
478
479            public void run() {
480                //Log.d(TAG, "entering main sensor thread");
481                final float[] values = new float[3];
482                final int[] status = new int[1];
483                final long timestamp[] = new long[1];
484                Process.setThreadPriority(Process.THREAD_PRIORITY_URGENT_DISPLAY);
485
486                if (!open()) {
487                    return;
488                }
489
490                synchronized (this) {
491                    // we've open the driver, we're ready to open the sensors
492                    mSensorsReady = true;
493                    this.notify();
494                }
495
496                while (true) {
497                    // wait for an event
498                    final int sensor = sensors_data_poll(sQueue, values, status, timestamp);
499
500                    int accuracy = status[0];
501                    synchronized (sListeners) {
502                        if (sensor == -1 || sListeners.isEmpty()) {
503                            // we lost the connection to the event stream. this happens
504                            // when the last listener is removed or if there is an error
505                            if (sensor == -1 && !sListeners.isEmpty()) {
506                                // log a warning in case of abnormal termination
507                                Log.e(TAG, "_sensors_data_poll() failed, we bail out: sensors=" + sensor);
508                            }
509                            // we have no more listeners or polling failed, terminate the thread
510                            sensors_destroy_queue(sQueue);
511                            sQueue = 0;
512                            mThread = null;
513                            break;
514                        }
515                        final Sensor sensorObject = sHandleToSensor.get(sensor);
516                        if (sensorObject != null) {
517                            // report the sensor event to all listeners that
518                            // care about it.
519                            final int size = sListeners.size();
520                            for (int i=0 ; i<size ; i++) {
521                                ListenerDelegate listener = sListeners.get(i);
522                                if (listener.hasSensor(sensorObject)) {
523                                    // this is asynchronous (okay to call
524                                    // with sListeners lock held).
525                                    listener.onSensorChangedLocked(sensorObject,
526                                            values, timestamp, accuracy);
527                                }
528                            }
529                        }
530                    }
531                }
532                //Log.d(TAG, "exiting main sensor thread");
533            }
534        }
535    }
536
537    /*-----------------------------------------------------------------------*/
538
539    private class ListenerDelegate {
540        private final SensorEventListener mSensorEventListener;
541        private final ArrayList<Sensor> mSensorList = new ArrayList<Sensor>();
542        private final Handler mHandler;
543        public SparseBooleanArray mSensors = new SparseBooleanArray();
544        public SparseBooleanArray mFirstEvent = new SparseBooleanArray();
545        public SparseIntArray mSensorAccuracies = new SparseIntArray();
546
547        ListenerDelegate(SensorEventListener listener, Sensor sensor, Handler handler) {
548            mSensorEventListener = listener;
549            Looper looper = (handler != null) ? handler.getLooper() : mMainLooper;
550            // currently we create one Handler instance per listener, but we could
551            // have one per looper (we'd need to pass the ListenerDelegate
552            // instance to handleMessage and keep track of them separately).
553            mHandler = new Handler(looper) {
554                @Override
555                public void handleMessage(Message msg) {
556                    final SensorEvent t = (SensorEvent)msg.obj;
557                    final int handle = t.sensor.getHandle();
558
559                    switch (t.sensor.getType()) {
560                        // Only report accuracy for sensors that support it.
561                        case Sensor.TYPE_MAGNETIC_FIELD:
562                        case Sensor.TYPE_ORIENTATION:
563                            // call onAccuracyChanged() only if the value changes
564                            final int accuracy = mSensorAccuracies.get(handle);
565                            if ((t.accuracy >= 0) && (accuracy != t.accuracy)) {
566                                mSensorAccuracies.put(handle, t.accuracy);
567                                mSensorEventListener.onAccuracyChanged(t.sensor, t.accuracy);
568                            }
569                            break;
570                        default:
571                            // For other sensors, just report the accuracy once
572                            if (mFirstEvent.get(handle) == false) {
573                                mFirstEvent.put(handle, true);
574                                mSensorEventListener.onAccuracyChanged(
575                                        t.sensor, SENSOR_STATUS_ACCURACY_HIGH);
576                            }
577                            break;
578                    }
579
580                    mSensorEventListener.onSensorChanged(t);
581                    sPool.returnToPool(t);
582                }
583            };
584            addSensor(sensor);
585        }
586
587        Object getListener() {
588            return mSensorEventListener;
589        }
590
591        void addSensor(Sensor sensor) {
592            mSensors.put(sensor.getHandle(), true);
593            mSensorList.add(sensor);
594        }
595        int removeSensor(Sensor sensor) {
596            mSensors.delete(sensor.getHandle());
597            mSensorList.remove(sensor);
598            return mSensors.size();
599        }
600        boolean hasSensor(Sensor sensor) {
601            return mSensors.get(sensor.getHandle());
602        }
603        List<Sensor> getSensors() {
604            return mSensorList;
605        }
606
607        void onSensorChangedLocked(Sensor sensor, float[] values, long[] timestamp, int accuracy) {
608            SensorEvent t = sPool.getFromPool();
609            final float[] v = t.values;
610            v[0] = values[0];
611            v[1] = values[1];
612            v[2] = values[2];
613            t.timestamp = timestamp[0];
614            t.accuracy = accuracy;
615            t.sensor = sensor;
616            Message msg = Message.obtain();
617            msg.what = 0;
618            msg.obj = t;
619            mHandler.sendMessage(msg);
620        }
621    }
622
623    /**
624     * {@hide}
625     */
626    public SensorManager(Looper mainLooper) {
627        mMainLooper = mainLooper;
628
629
630        synchronized(sListeners) {
631            if (!sSensorModuleInitialized) {
632                sSensorModuleInitialized = true;
633
634                nativeClassInit();
635
636                sWindowManager = IWindowManager.Stub.asInterface(
637                        ServiceManager.getService("window"));
638                if (sWindowManager != null) {
639                    // if it's null we're running in the system process
640                    // which won't get the rotated values
641                    try {
642                        sRotation = sWindowManager.watchRotation(
643                                new IRotationWatcher.Stub() {
644                                    public void onRotationChanged(int rotation) {
645                                        SensorManager.this.onRotationChanged(rotation);
646                                    }
647                                }
648                        );
649                    } catch (RemoteException e) {
650                    }
651                }
652
653                // initialize the sensor list
654                sensors_module_init();
655                final ArrayList<Sensor> fullList = sFullSensorsList;
656                int i = 0;
657                do {
658                    Sensor sensor = new Sensor();
659                    i = sensors_module_get_next_sensor(sensor, i);
660
661                    if (i>=0) {
662                        //Log.d(TAG, "found sensor: " + sensor.getName() +
663                        //        ", handle=" + sensor.getHandle());
664                        sensor.setLegacyType(getLegacySensorType(sensor.getType()));
665                        fullList.add(sensor);
666                        sHandleToSensor.append(sensor.getHandle(), sensor);
667                    }
668                } while (i>0);
669
670                sPool = new SensorEventPool( sFullSensorsList.size()*2 );
671                sSensorThread = new SensorThread();
672            }
673        }
674    }
675
676    private int getLegacySensorType(int type) {
677        switch (type) {
678            case Sensor.TYPE_ACCELEROMETER:
679                return SENSOR_ACCELEROMETER;
680            case Sensor.TYPE_MAGNETIC_FIELD:
681                return SENSOR_MAGNETIC_FIELD;
682            case Sensor.TYPE_ORIENTATION:
683                return SENSOR_ORIENTATION_RAW;
684            case Sensor.TYPE_TEMPERATURE:
685                return SENSOR_TEMPERATURE;
686        }
687        return 0;
688    }
689
690    /**
691     * @return available sensors.
692     * @deprecated This method is deprecated, use
693     *             {@link SensorManager#getSensorList(int)} instead
694     */
695    @Deprecated
696    public int getSensors() {
697        int result = 0;
698        final ArrayList<Sensor> fullList = sFullSensorsList;
699        for (Sensor i : fullList) {
700            switch (i.getType()) {
701                case Sensor.TYPE_ACCELEROMETER:
702                    result |= SensorManager.SENSOR_ACCELEROMETER;
703                    break;
704                case Sensor.TYPE_MAGNETIC_FIELD:
705                    result |= SensorManager.SENSOR_MAGNETIC_FIELD;
706                    break;
707                case Sensor.TYPE_ORIENTATION:
708                    result |= SensorManager.SENSOR_ORIENTATION |
709                    SensorManager.SENSOR_ORIENTATION_RAW;
710                    break;
711            }
712        }
713        return result;
714    }
715
716    /**
717     * Use this method to get the list of available sensors of a certain type.
718     * Make multiple calls to get sensors of different types or use
719     * {@link android.hardware.Sensor#TYPE_ALL Sensor.TYPE_ALL} to get all the
720     * sensors.
721     *
722     * @param type
723     *        of sensors requested
724     *
725     * @return a list of sensors matching the asked type.
726     *
727     * @see #getDefaultSensor(int)
728     * @see Sensor
729     */
730    public List<Sensor> getSensorList(int type) {
731        // cache the returned lists the first time
732        List<Sensor> list;
733        final ArrayList<Sensor> fullList = sFullSensorsList;
734        synchronized(fullList) {
735            list = sSensorListByType.get(type);
736            if (list == null) {
737                if (type == Sensor.TYPE_ALL) {
738                    list = fullList;
739                } else {
740                    list = new ArrayList<Sensor>();
741                    for (Sensor i : fullList) {
742                        if (i.getType() == type)
743                            list.add(i);
744                    }
745                }
746                list = Collections.unmodifiableList(list);
747                sSensorListByType.append(type, list);
748            }
749        }
750        return list;
751    }
752
753    /**
754     * Use this method to get the default sensor for a given type. Note that the
755     * returned sensor could be a composite sensor, and its data could be
756     * averaged or filtered. If you need to access the raw sensors use
757     * {@link SensorManager#getSensorList(int) getSensorList}.
758     *
759     * @param type
760     *        of sensors requested
761     *
762     * @return the default sensors matching the asked type.
763     *
764     * @see #getSensorList(int)
765     * @see Sensor
766     */
767    public Sensor getDefaultSensor(int type) {
768        // TODO: need to be smarter, for now, just return the 1st sensor
769        List<Sensor> l = getSensorList(type);
770        return l.isEmpty() ? null : l.get(0);
771    }
772
773    /**
774     * Registers a listener for given sensors.
775     *
776     * @deprecated This method is deprecated, use
777     *             {@link SensorManager#registerListener(SensorEventListener, Sensor, int)}
778     *             instead.
779     *
780     * @param listener
781     *        sensor listener object
782     *
783     * @param sensors
784     *        a bit masks of the sensors to register to
785     *
786     * @return <code>true</code> if the sensor is supported and successfully
787     *         enabled
788     */
789    @Deprecated
790    public boolean registerListener(SensorListener listener, int sensors) {
791        return registerListener(listener, sensors, SENSOR_DELAY_NORMAL);
792    }
793
794    /**
795     * Registers a SensorListener for given sensors.
796     *
797     * @deprecated This method is deprecated, use
798     *             {@link SensorManager#registerListener(SensorEventListener, Sensor, int)}
799     *             instead.
800     *
801     * @param listener
802     *        sensor listener object
803     *
804     * @param sensors
805     *        a bit masks of the sensors to register to
806     *
807     * @param rate
808     *        rate of events. This is only a hint to the system. events may be
809     *        received faster or slower than the specified rate. Usually events
810     *        are received faster. The value must be one of
811     *        {@link #SENSOR_DELAY_NORMAL}, {@link #SENSOR_DELAY_UI},
812     *        {@link #SENSOR_DELAY_GAME}, or {@link #SENSOR_DELAY_FASTEST}.
813     *
814     * @return <code>true</code> if the sensor is supported and successfully
815     *         enabled
816     */
817    @Deprecated
818    public boolean registerListener(SensorListener listener, int sensors, int rate) {
819        if (listener == null) {
820            return false;
821        }
822        boolean result = false;
823        result = registerLegacyListener(SENSOR_ACCELEROMETER, Sensor.TYPE_ACCELEROMETER,
824                listener, sensors, rate) || result;
825        result = registerLegacyListener(SENSOR_MAGNETIC_FIELD, Sensor.TYPE_MAGNETIC_FIELD,
826                listener, sensors, rate) || result;
827        result = registerLegacyListener(SENSOR_ORIENTATION_RAW, Sensor.TYPE_ORIENTATION,
828                listener, sensors, rate) || result;
829        result = registerLegacyListener(SENSOR_ORIENTATION, Sensor.TYPE_ORIENTATION,
830                listener, sensors, rate) || result;
831        result = registerLegacyListener(SENSOR_TEMPERATURE, Sensor.TYPE_TEMPERATURE,
832                listener, sensors, rate) || result;
833        return result;
834    }
835
836    @SuppressWarnings("deprecation")
837    private boolean registerLegacyListener(int legacyType, int type,
838            SensorListener listener, int sensors, int rate)
839    {
840        if (listener == null) {
841            return false;
842        }
843        boolean result = false;
844        // Are we activating this legacy sensor?
845        if ((sensors & legacyType) != 0) {
846            // if so, find a suitable Sensor
847            Sensor sensor = getDefaultSensor(type);
848            if (sensor != null) {
849                // If we don't already have one, create a LegacyListener
850                // to wrap this listener and process the events as
851                // they are expected by legacy apps.
852                LegacyListener legacyListener = null;
853                synchronized (mLegacyListenersMap) {
854                    legacyListener = mLegacyListenersMap.get(listener);
855                    if (legacyListener == null) {
856                        // we didn't find a LegacyListener for this client,
857                        // create one, and put it in our list.
858                        legacyListener = new LegacyListener(listener);
859                        mLegacyListenersMap.put(listener, legacyListener);
860                    }
861                }
862                // register this legacy sensor with this legacy listener
863                legacyListener.registerSensor(legacyType);
864                // and finally, register the legacy listener with the new apis
865                result = registerListener(legacyListener, sensor, rate);
866            }
867        }
868        return result;
869    }
870
871    /**
872     * Unregisters a listener for the sensors with which it is registered.
873     *
874     * @deprecated This method is deprecated, use
875     *             {@link SensorManager#unregisterListener(SensorEventListener, Sensor)}
876     *             instead.
877     *
878     * @param listener
879     *        a SensorListener object
880     *
881     * @param sensors
882     *        a bit masks of the sensors to unregister from
883     */
884    @Deprecated
885    public void unregisterListener(SensorListener listener, int sensors) {
886        unregisterLegacyListener(SENSOR_ACCELEROMETER, Sensor.TYPE_ACCELEROMETER,
887                listener, sensors);
888        unregisterLegacyListener(SENSOR_MAGNETIC_FIELD, Sensor.TYPE_MAGNETIC_FIELD,
889                listener, sensors);
890        unregisterLegacyListener(SENSOR_ORIENTATION_RAW, Sensor.TYPE_ORIENTATION,
891                listener, sensors);
892        unregisterLegacyListener(SENSOR_ORIENTATION, Sensor.TYPE_ORIENTATION,
893                listener, sensors);
894        unregisterLegacyListener(SENSOR_TEMPERATURE, Sensor.TYPE_TEMPERATURE,
895                listener, sensors);
896    }
897
898    @SuppressWarnings("deprecation")
899    private void unregisterLegacyListener(int legacyType, int type,
900            SensorListener listener, int sensors)
901    {
902        if (listener == null) {
903            return;
904        }
905        // do we know about this listener?
906        LegacyListener legacyListener = null;
907        synchronized (mLegacyListenersMap) {
908            legacyListener = mLegacyListenersMap.get(listener);
909        }
910        if (legacyListener != null) {
911            // Are we deactivating this legacy sensor?
912            if ((sensors & legacyType) != 0) {
913                // if so, find the corresponding Sensor
914                Sensor sensor = getDefaultSensor(type);
915                if (sensor != null) {
916                    // unregister this legacy sensor and if we don't
917                    // need the corresponding Sensor, unregister it too
918                    if (legacyListener.unregisterSensor(legacyType)) {
919                        // corresponding sensor not needed, unregister
920                        unregisterListener(legacyListener, sensor);
921                        // finally check if we still need the legacyListener
922                        // in our mapping, if not, get rid of it too.
923                        synchronized(sListeners) {
924                            boolean found = false;
925                            for (ListenerDelegate i : sListeners) {
926                                if (i.getListener() == legacyListener) {
927                                    found = true;
928                                    break;
929                                }
930                            }
931                            if (!found) {
932                                synchronized (mLegacyListenersMap) {
933                                    mLegacyListenersMap.remove(listener);
934                                }
935                            }
936                        }
937                    }
938                }
939            }
940        }
941    }
942
943    /**
944     * Unregisters a listener for all sensors.
945     *
946     * @deprecated This method is deprecated, use
947     *             {@link SensorManager#unregisterListener(SensorEventListener)}
948     *             instead.
949     *
950     * @param listener
951     *        a SensorListener object
952     */
953    @Deprecated
954    public void unregisterListener(SensorListener listener) {
955        unregisterListener(listener, SENSOR_ALL | SENSOR_ORIENTATION_RAW);
956    }
957
958    /**
959     * Unregisters a listener for the sensors with which it is registered.
960     *
961     * @param listener
962     *        a SensorEventListener object
963     *
964     * @param sensor
965     *        the sensor to unregister from
966     *
967     * @see #unregisterListener(SensorEventListener)
968     * @see #registerListener(SensorEventListener, Sensor, int)
969     *
970     */
971    public void unregisterListener(SensorEventListener listener, Sensor sensor) {
972        unregisterListener((Object)listener, sensor);
973    }
974
975    /**
976     * Unregisters a listener for all sensors.
977     *
978     * @param listener
979     *        a SensorListener object
980     *
981     * @see #unregisterListener(SensorEventListener, Sensor)
982     * @see #registerListener(SensorEventListener, Sensor, int)
983     *
984     */
985    public void unregisterListener(SensorEventListener listener) {
986        unregisterListener((Object)listener);
987    }
988
989    /**
990     * Registers a {@link android.hardware.SensorEventListener
991     * SensorEventListener} for the given sensor.
992     *
993     * @param listener
994     *        A {@link android.hardware.SensorEventListener SensorEventListener}
995     *        object.
996     *
997     * @param sensor
998     *        The {@link android.hardware.Sensor Sensor} to register to.
999     *
1000     * @param rate
1001     *        The rate {@link android.hardware.SensorEvent sensor events} are
1002     *        delivered at. This is only a hint to the system. Events may be
1003     *        received faster or slower than the specified rate. Usually events
1004     *        are received faster. The value must be one of
1005     *        {@link #SENSOR_DELAY_NORMAL}, {@link #SENSOR_DELAY_UI},
1006     *        {@link #SENSOR_DELAY_GAME}, or {@link #SENSOR_DELAY_FASTEST}
1007     *        or, the desired delay between events in microsecond.
1008     *
1009     * @return <code>true</code> if the sensor is supported and successfully
1010     *         enabled.
1011     *
1012     * @see #registerListener(SensorEventListener, Sensor, int, Handler)
1013     * @see #unregisterListener(SensorEventListener)
1014     * @see #unregisterListener(SensorEventListener, Sensor)
1015     *
1016     */
1017    public boolean registerListener(SensorEventListener listener, Sensor sensor, int rate) {
1018        return registerListener(listener, sensor, rate, null);
1019    }
1020
1021    private boolean enableSensorLocked(Sensor sensor, int delay) {
1022        boolean result = false;
1023        for (ListenerDelegate i : sListeners) {
1024            if (i.hasSensor(sensor)) {
1025                String name = sensor.getName();
1026                int handle = sensor.getHandle();
1027                result = sensors_enable_sensor(sQueue, name, handle, delay);
1028                break;
1029            }
1030        }
1031        return result;
1032    }
1033
1034    private boolean disableSensorLocked(Sensor sensor) {
1035        for (ListenerDelegate i : sListeners) {
1036            if (i.hasSensor(sensor)) {
1037                // not an error, it's just that this sensor is still in use
1038                return true;
1039            }
1040        }
1041        String name = sensor.getName();
1042        int handle = sensor.getHandle();
1043        return sensors_enable_sensor(sQueue, name, handle, SENSOR_DISABLE);
1044    }
1045
1046    /**
1047     * Registers a {@link android.hardware.SensorEventListener
1048     * SensorEventListener} for the given sensor.
1049     *
1050     * @param listener
1051     *        A {@link android.hardware.SensorEventListener SensorEventListener}
1052     *        object.
1053     *
1054     * @param sensor
1055     *        The {@link android.hardware.Sensor Sensor} to register to.
1056     *
1057     * @param rate
1058     *        The rate {@link android.hardware.SensorEvent sensor events} are
1059     *        delivered at. This is only a hint to the system. Events may be
1060     *        received faster or slower than the specified rate. Usually events
1061     *        are received faster. The value must be one of
1062     *        {@link #SENSOR_DELAY_NORMAL}, {@link #SENSOR_DELAY_UI},
1063     *        {@link #SENSOR_DELAY_GAME}, or {@link #SENSOR_DELAY_FASTEST}.
1064     *        or, the desired delay between events in microsecond.
1065     *
1066     * @param handler
1067     *        The {@link android.os.Handler Handler} the
1068     *        {@link android.hardware.SensorEvent sensor events} will be
1069     *        delivered to.
1070     *
1071     * @return true if the sensor is supported and successfully enabled.
1072     *
1073     * @see #registerListener(SensorEventListener, Sensor, int)
1074     * @see #unregisterListener(SensorEventListener)
1075     * @see #unregisterListener(SensorEventListener, Sensor)
1076     *
1077     */
1078    public boolean registerListener(SensorEventListener listener, Sensor sensor, int rate,
1079            Handler handler) {
1080        if (listener == null || sensor == null) {
1081            return false;
1082        }
1083        boolean result = true;
1084        int delay = -1;
1085        switch (rate) {
1086            case SENSOR_DELAY_FASTEST:
1087                delay = 0;
1088                break;
1089            case SENSOR_DELAY_GAME:
1090                delay = 20000;
1091                break;
1092            case SENSOR_DELAY_UI:
1093                delay = 66667;
1094                break;
1095            case SENSOR_DELAY_NORMAL:
1096                delay = 200000;
1097                break;
1098            default:
1099                delay = rate;
1100                break;
1101        }
1102
1103        synchronized (sListeners) {
1104            // look for this listener in our list
1105            ListenerDelegate l = null;
1106            for (ListenerDelegate i : sListeners) {
1107                if (i.getListener() == listener) {
1108                    l = i;
1109                    break;
1110                }
1111            }
1112
1113            // if we don't find it, add it to the list
1114            if (l == null) {
1115                l = new ListenerDelegate(listener, sensor, handler);
1116                sListeners.add(l);
1117                // if the list is not empty, start our main thread
1118                if (!sListeners.isEmpty()) {
1119                    if (sSensorThread.startLocked()) {
1120                        if (!enableSensorLocked(sensor, delay)) {
1121                            // oops. there was an error
1122                            sListeners.remove(l);
1123                            result = false;
1124                        }
1125                    } else {
1126                        // there was an error, remove the listener
1127                        sListeners.remove(l);
1128                        result = false;
1129                    }
1130                } else {
1131                    // weird, we couldn't add the listener
1132                    result = false;
1133                }
1134            } else {
1135                l.addSensor(sensor);
1136                if (!enableSensorLocked(sensor, delay)) {
1137                    // oops. there was an error
1138                    l.removeSensor(sensor);
1139                    result = false;
1140                }
1141            }
1142        }
1143
1144        return result;
1145    }
1146
1147    private void unregisterListener(Object listener, Sensor sensor) {
1148        if (listener == null || sensor == null) {
1149            return;
1150        }
1151
1152        synchronized (sListeners) {
1153            final int size = sListeners.size();
1154            for (int i=0 ; i<size ; i++) {
1155                ListenerDelegate l = sListeners.get(i);
1156                if (l.getListener() == listener) {
1157                    if (l.removeSensor(sensor) == 0) {
1158                        // if we have no more sensors enabled on this listener,
1159                        // take it off the list.
1160                        sListeners.remove(i);
1161                    }
1162                    break;
1163                }
1164            }
1165            disableSensorLocked(sensor);
1166        }
1167    }
1168
1169    private void unregisterListener(Object listener) {
1170        if (listener == null) {
1171            return;
1172        }
1173
1174        synchronized (sListeners) {
1175            final int size = sListeners.size();
1176            for (int i=0 ; i<size ; i++) {
1177                ListenerDelegate l = sListeners.get(i);
1178                if (l.getListener() == listener) {
1179                    sListeners.remove(i);
1180                    // disable all sensors for this listener
1181                    for (Sensor sensor : l.getSensors()) {
1182                        disableSensorLocked(sensor);
1183                    }
1184                    break;
1185                }
1186            }
1187        }
1188    }
1189
1190    /**
1191     * <p>
1192     * Computes the inclination matrix <b>I</b> as well as the rotation matrix
1193     * <b>R</b> transforming a vector from the device coordinate system to the
1194     * world's coordinate system which is defined as a direct orthonormal basis,
1195     * where:
1196     * </p>
1197     *
1198     * <ul>
1199     * <li>X is defined as the vector product <b>Y.Z</b> (It is tangential to
1200     * the ground at the device's current location and roughly points East).</li>
1201     * <li>Y is tangential to the ground at the device's current location and
1202     * points towards the magnetic North Pole.</li>
1203     * <li>Z points towards the sky and is perpendicular to the ground.</li>
1204     * </ul>
1205     *
1206     * <p>
1207     * <center><img src="../../../images/axis_globe.png"
1208     * alt="World coordinate-system diagram." border="0" /></center>
1209     * </p>
1210     *
1211     * <p>
1212     * <hr>
1213     * <p>
1214     * By definition:
1215     * <p>
1216     * [0 0 g] = <b>R</b> * <b>gravity</b> (g = magnitude of gravity)
1217     * <p>
1218     * [0 m 0] = <b>I</b> * <b>R</b> * <b>geomagnetic</b> (m = magnitude of
1219     * geomagnetic field)
1220     * <p>
1221     * <b>R</b> is the identity matrix when the device is aligned with the
1222     * world's coordinate system, that is, when the device's X axis points
1223     * toward East, the Y axis points to the North Pole and the device is facing
1224     * the sky.
1225     *
1226     * <p>
1227     * <b>I</b> is a rotation matrix transforming the geomagnetic vector into
1228     * the same coordinate space as gravity (the world's coordinate space).
1229     * <b>I</b> is a simple rotation around the X axis. The inclination angle in
1230     * radians can be computed with {@link #getInclination}.
1231     * <hr>
1232     *
1233     * <p>
1234     * Each matrix is returned either as a 3x3 or 4x4 row-major matrix depending
1235     * on the length of the passed array:
1236     * <p>
1237     * <u>If the array length is 16:</u>
1238     *
1239     * <pre>
1240     *   /  M[ 0]   M[ 1]   M[ 2]   M[ 3]  \
1241     *   |  M[ 4]   M[ 5]   M[ 6]   M[ 7]  |
1242     *   |  M[ 8]   M[ 9]   M[10]   M[11]  |
1243     *   \  M[12]   M[13]   M[14]   M[15]  /
1244     *</pre>
1245     *
1246     * This matrix is ready to be used by OpenGL ES's
1247     * {@link javax.microedition.khronos.opengles.GL10#glLoadMatrixf(float[], int)
1248     * glLoadMatrixf(float[], int)}.
1249     * <p>
1250     * Note that because OpenGL matrices are column-major matrices you must
1251     * transpose the matrix before using it. However, since the matrix is a
1252     * rotation matrix, its transpose is also its inverse, conveniently, it is
1253     * often the inverse of the rotation that is needed for rendering; it can
1254     * therefore be used with OpenGL ES directly.
1255     * <p>
1256     * Also note that the returned matrices always have this form:
1257     *
1258     * <pre>
1259     *   /  M[ 0]   M[ 1]   M[ 2]   0  \
1260     *   |  M[ 4]   M[ 5]   M[ 6]   0  |
1261     *   |  M[ 8]   M[ 9]   M[10]   0  |
1262     *   \      0       0       0   1  /
1263     *</pre>
1264     *
1265     * <p>
1266     * <u>If the array length is 9:</u>
1267     *
1268     * <pre>
1269     *   /  M[ 0]   M[ 1]   M[ 2]  \
1270     *   |  M[ 3]   M[ 4]   M[ 5]  |
1271     *   \  M[ 6]   M[ 7]   M[ 8]  /
1272     *</pre>
1273     *
1274     * <hr>
1275     * <p>
1276     * The inverse of each matrix can be computed easily by taking its
1277     * transpose.
1278     *
1279     * <p>
1280     * The matrices returned by this function are meaningful only when the
1281     * device is not free-falling and it is not close to the magnetic north. If
1282     * the device is accelerating, or placed into a strong magnetic field, the
1283     * returned matrices may be inaccurate.
1284     *
1285     * @param R
1286     *        is an array of 9 floats holding the rotation matrix <b>R</b> when
1287     *        this function returns. R can be null.
1288     *        <p>
1289     *
1290     * @param I
1291     *        is an array of 9 floats holding the rotation matrix <b>I</b> when
1292     *        this function returns. I can be null.
1293     *        <p>
1294     *
1295     * @param gravity
1296     *        is an array of 3 floats containing the gravity vector expressed in
1297     *        the device's coordinate. You can simply use the
1298     *        {@link android.hardware.SensorEvent#values values} returned by a
1299     *        {@link android.hardware.SensorEvent SensorEvent} of a
1300     *        {@link android.hardware.Sensor Sensor} of type
1301     *        {@link android.hardware.Sensor#TYPE_ACCELEROMETER
1302     *        TYPE_ACCELEROMETER}.
1303     *        <p>
1304     *
1305     * @param geomagnetic
1306     *        is an array of 3 floats containing the geomagnetic vector
1307     *        expressed in the device's coordinate. You can simply use the
1308     *        {@link android.hardware.SensorEvent#values values} returned by a
1309     *        {@link android.hardware.SensorEvent SensorEvent} of a
1310     *        {@link android.hardware.Sensor Sensor} of type
1311     *        {@link android.hardware.Sensor#TYPE_MAGNETIC_FIELD
1312     *        TYPE_MAGNETIC_FIELD}.
1313     *
1314     * @return <code>true</code> on success, <code>false</code> on failure (for
1315     *         instance, if the device is in free fall). On failure the output
1316     *         matrices are not modified.
1317     *
1318     * @see #getInclination(float[])
1319     * @see #getOrientation(float[], float[])
1320     * @see #remapCoordinateSystem(float[], int, int, float[])
1321     */
1322
1323    public static boolean getRotationMatrix(float[] R, float[] I,
1324            float[] gravity, float[] geomagnetic) {
1325        // TODO: move this to native code for efficiency
1326        float Ax = gravity[0];
1327        float Ay = gravity[1];
1328        float Az = gravity[2];
1329        final float Ex = geomagnetic[0];
1330        final float Ey = geomagnetic[1];
1331        final float Ez = geomagnetic[2];
1332        float Hx = Ey*Az - Ez*Ay;
1333        float Hy = Ez*Ax - Ex*Az;
1334        float Hz = Ex*Ay - Ey*Ax;
1335        final float normH = (float)Math.sqrt(Hx*Hx + Hy*Hy + Hz*Hz);
1336        if (normH < 0.1f) {
1337            // device is close to free fall (or in space?), or close to
1338            // magnetic north pole. Typical values are  > 100.
1339            return false;
1340        }
1341        final float invH = 1.0f / normH;
1342        Hx *= invH;
1343        Hy *= invH;
1344        Hz *= invH;
1345        final float invA = 1.0f / (float)Math.sqrt(Ax*Ax + Ay*Ay + Az*Az);
1346        Ax *= invA;
1347        Ay *= invA;
1348        Az *= invA;
1349        final float Mx = Ay*Hz - Az*Hy;
1350        final float My = Az*Hx - Ax*Hz;
1351        final float Mz = Ax*Hy - Ay*Hx;
1352        if (R != null) {
1353            if (R.length == 9) {
1354                R[0] = Hx;     R[1] = Hy;     R[2] = Hz;
1355                R[3] = Mx;     R[4] = My;     R[5] = Mz;
1356                R[6] = Ax;     R[7] = Ay;     R[8] = Az;
1357            } else if (R.length == 16) {
1358                R[0]  = Hx;    R[1]  = Hy;    R[2]  = Hz;   R[3]  = 0;
1359                R[4]  = Mx;    R[5]  = My;    R[6]  = Mz;   R[7]  = 0;
1360                R[8]  = Ax;    R[9]  = Ay;    R[10] = Az;   R[11] = 0;
1361                R[12] = 0;     R[13] = 0;     R[14] = 0;    R[15] = 1;
1362            }
1363        }
1364        if (I != null) {
1365            // compute the inclination matrix by projecting the geomagnetic
1366            // vector onto the Z (gravity) and X (horizontal component
1367            // of geomagnetic vector) axes.
1368            final float invE = 1.0f / (float)Math.sqrt(Ex*Ex + Ey*Ey + Ez*Ez);
1369            final float c = (Ex*Mx + Ey*My + Ez*Mz) * invE;
1370            final float s = (Ex*Ax + Ey*Ay + Ez*Az) * invE;
1371            if (I.length == 9) {
1372                I[0] = 1;     I[1] = 0;     I[2] = 0;
1373                I[3] = 0;     I[4] = c;     I[5] = s;
1374                I[6] = 0;     I[7] =-s;     I[8] = c;
1375            } else if (I.length == 16) {
1376                I[0] = 1;     I[1] = 0;     I[2] = 0;
1377                I[4] = 0;     I[5] = c;     I[6] = s;
1378                I[8] = 0;     I[9] =-s;     I[10]= c;
1379                I[3] = I[7] = I[11] = I[12] = I[13] = I[14] = 0;
1380                I[15] = 1;
1381            }
1382        }
1383        return true;
1384    }
1385
1386    /**
1387     * Computes the geomagnetic inclination angle in radians from the
1388     * inclination matrix <b>I</b> returned by {@link #getRotationMatrix}.
1389     *
1390     * @param I
1391     *        inclination matrix see {@link #getRotationMatrix}.
1392     *
1393     * @return The geomagnetic inclination angle in radians.
1394     *
1395     * @see #getRotationMatrix(float[], float[], float[], float[])
1396     * @see #getOrientation(float[], float[])
1397     * @see GeomagneticField
1398     *
1399     */
1400    public static float getInclination(float[] I) {
1401        if (I.length == 9) {
1402            return (float)Math.atan2(I[5], I[4]);
1403        } else {
1404            return (float)Math.atan2(I[6], I[5]);
1405        }
1406    }
1407
1408    /**
1409     * <p>
1410     * Rotates the supplied rotation matrix so it is expressed in a different
1411     * coordinate system. This is typically used when an application needs to
1412     * compute the three orientation angles of the device (see
1413     * {@link #getOrientation}) in a different coordinate system.
1414     * </p>
1415     *
1416     * <p>
1417     * When the rotation matrix is used for drawing (for instance with OpenGL
1418     * ES), it usually <b>doesn't need</b> to be transformed by this function,
1419     * unless the screen is physically rotated, in which case you can use
1420     * {@link android.view.Display#getRotation() Display.getRotation()} to
1421     * retrieve the current rotation of the screen. Note that because the user
1422     * is generally free to rotate their screen, you often should consider the
1423     * rotation in deciding the parameters to use here.
1424     * </p>
1425     *
1426     * <p>
1427     * <u>Examples:</u>
1428     * <p>
1429     *
1430     * <ul>
1431     * <li>Using the camera (Y axis along the camera's axis) for an augmented
1432     * reality application where the rotation angles are needed:</li>
1433     *
1434     * <p>
1435     * <ul>
1436     * <code>remapCoordinateSystem(inR, AXIS_X, AXIS_Z, outR);</code>
1437     * </ul>
1438     * </p>
1439     *
1440     * <li>Using the device as a mechanical compass when rotation is
1441     * {@link android.view.Surface#ROTATION_90 Surface.ROTATION_90}:</li>
1442     *
1443     * <p>
1444     * <ul>
1445     * <code>remapCoordinateSystem(inR, AXIS_Y, AXIS_MINUS_X, outR);</code>
1446     * </ul>
1447     * </p>
1448     *
1449     * Beware of the above example. This call is needed only to account for a
1450     * rotation from its natural orientation when calculating the rotation
1451     * angles (see {@link #getOrientation}). If the rotation matrix is also used
1452     * for rendering, it may not need to be transformed, for instance if your
1453     * {@link android.app.Activity Activity} is running in landscape mode.
1454     * </ul>
1455     *
1456     * <p>
1457     * Since the resulting coordinate system is orthonormal, only two axes need
1458     * to be specified.
1459     *
1460     * @param inR
1461     *        the rotation matrix to be transformed. Usually it is the matrix
1462     *        returned by {@link #getRotationMatrix}.
1463     *
1464     * @param X
1465     *        defines on which world axis and direction the X axis of the device
1466     *        is mapped.
1467     *
1468     * @param Y
1469     *        defines on which world axis and direction the Y axis of the device
1470     *        is mapped.
1471     *
1472     * @param outR
1473     *        the transformed rotation matrix. inR and outR can be the same
1474     *        array, but it is not recommended for performance reason.
1475     *
1476     * @return <code>true</code> on success. <code>false</code> if the input
1477     *         parameters are incorrect, for instance if X and Y define the same
1478     *         axis. Or if inR and outR don't have the same length.
1479     *
1480     * @see #getRotationMatrix(float[], float[], float[], float[])
1481     */
1482
1483    public static boolean remapCoordinateSystem(float[] inR, int X, int Y,
1484            float[] outR)
1485    {
1486        if (inR == outR) {
1487            final float[] temp = mTempMatrix;
1488            synchronized(temp) {
1489                // we don't expect to have a lot of contention
1490                if (remapCoordinateSystemImpl(inR, X, Y, temp)) {
1491                    final int size = outR.length;
1492                    for (int i=0 ; i<size ; i++)
1493                        outR[i] = temp[i];
1494                    return true;
1495                }
1496            }
1497        }
1498        return remapCoordinateSystemImpl(inR, X, Y, outR);
1499    }
1500
1501    private static boolean remapCoordinateSystemImpl(float[] inR, int X, int Y,
1502            float[] outR)
1503    {
1504        /*
1505         * X and Y define a rotation matrix 'r':
1506         *
1507         *  (X==1)?((X&0x80)?-1:1):0    (X==2)?((X&0x80)?-1:1):0    (X==3)?((X&0x80)?-1:1):0
1508         *  (Y==1)?((Y&0x80)?-1:1):0    (Y==2)?((Y&0x80)?-1:1):0    (Y==3)?((X&0x80)?-1:1):0
1509         *                              r[0] ^ r[1]
1510         *
1511         * where the 3rd line is the vector product of the first 2 lines
1512         *
1513         */
1514
1515        final int length = outR.length;
1516        if (inR.length != length)
1517            return false;   // invalid parameter
1518        if ((X & 0x7C)!=0 || (Y & 0x7C)!=0)
1519            return false;   // invalid parameter
1520        if (((X & 0x3)==0) || ((Y & 0x3)==0))
1521            return false;   // no axis specified
1522        if ((X & 0x3) == (Y & 0x3))
1523            return false;   // same axis specified
1524
1525        // Z is "the other" axis, its sign is either +/- sign(X)*sign(Y)
1526        // this can be calculated by exclusive-or'ing X and Y; except for
1527        // the sign inversion (+/-) which is calculated below.
1528        int Z = X ^ Y;
1529
1530        // extract the axis (remove the sign), offset in the range 0 to 2.
1531        final int x = (X & 0x3)-1;
1532        final int y = (Y & 0x3)-1;
1533        final int z = (Z & 0x3)-1;
1534
1535        // compute the sign of Z (whether it needs to be inverted)
1536        final int axis_y = (z+1)%3;
1537        final int axis_z = (z+2)%3;
1538        if (((x^axis_y)|(y^axis_z)) != 0)
1539            Z ^= 0x80;
1540
1541        final boolean sx = (X>=0x80);
1542        final boolean sy = (Y>=0x80);
1543        final boolean sz = (Z>=0x80);
1544
1545        // Perform R * r, in avoiding actual muls and adds.
1546        final int rowLength = ((length==16)?4:3);
1547        for (int j=0 ; j<3 ; j++) {
1548            final int offset = j*rowLength;
1549            for (int i=0 ; i<3 ; i++) {
1550                if (x==i)   outR[offset+i] = sx ? -inR[offset+0] : inR[offset+0];
1551                if (y==i)   outR[offset+i] = sy ? -inR[offset+1] : inR[offset+1];
1552                if (z==i)   outR[offset+i] = sz ? -inR[offset+2] : inR[offset+2];
1553            }
1554        }
1555        if (length == 16) {
1556            outR[3] = outR[7] = outR[11] = outR[12] = outR[13] = outR[14] = 0;
1557            outR[15] = 1;
1558        }
1559        return true;
1560    }
1561
1562    /**
1563     * Computes the device's orientation based on the rotation matrix.
1564     * <p>
1565     * When it returns, the array values is filled with the result:
1566     * <ul>
1567     * <li>values[0]: <i>azimuth</i>, rotation around the Z axis.</li>
1568     * <li>values[1]: <i>pitch</i>, rotation around the X axis.</li>
1569     * <li>values[2]: <i>roll</i>, rotation around the Y axis.</li>
1570     * </ul>
1571     * <p>The reference coordinate-system used is different from the world
1572     * coordinate-system defined for the rotation matrix:</p>
1573     * <ul>
1574     * <li>X is defined as the vector product <b>Y.Z</b> (It is tangential to
1575     * the ground at the device's current location and roughly points West).</li>
1576     * <li>Y is tangential to the ground at the device's current location and
1577     * points towards the magnetic North Pole.</li>
1578     * <li>Z points towards the center of the Earth and is perpendicular to the ground.</li>
1579     * </ul>
1580     *
1581     * <p>
1582     * <center><img src="../../../images/axis_globe_inverted.png"
1583     * alt="Inverted world coordinate-system diagram." border="0" /></center>
1584     * </p>
1585     * <p>
1586     * All three angles above are in <b>radians</b> and <b>positive</b> in the
1587     * <b>counter-clockwise</b> direction.
1588     *
1589     * @param R
1590     *        rotation matrix see {@link #getRotationMatrix}.
1591     *
1592     * @param values
1593     *        an array of 3 floats to hold the result.
1594     *
1595     * @return The array values passed as argument.
1596     *
1597     * @see #getRotationMatrix(float[], float[], float[], float[])
1598     * @see GeomagneticField
1599     */
1600    public static float[] getOrientation(float[] R, float values[]) {
1601        /*
1602         * 4x4 (length=16) case:
1603         *   /  R[ 0]   R[ 1]   R[ 2]   0  \
1604         *   |  R[ 4]   R[ 5]   R[ 6]   0  |
1605         *   |  R[ 8]   R[ 9]   R[10]   0  |
1606         *   \      0       0       0   1  /
1607         *
1608         * 3x3 (length=9) case:
1609         *   /  R[ 0]   R[ 1]   R[ 2]  \
1610         *   |  R[ 3]   R[ 4]   R[ 5]  |
1611         *   \  R[ 6]   R[ 7]   R[ 8]  /
1612         *
1613         */
1614        if (R.length == 9) {
1615            values[0] = (float)Math.atan2(R[1], R[4]);
1616            values[1] = (float)Math.asin(-R[7]);
1617            values[2] = (float)Math.atan2(-R[6], R[8]);
1618        } else {
1619            values[0] = (float)Math.atan2(R[1], R[5]);
1620            values[1] = (float)Math.asin(-R[9]);
1621            values[2] = (float)Math.atan2(-R[8], R[10]);
1622        }
1623        return values;
1624    }
1625
1626    /**
1627     * Computes the Altitude in meters from the atmospheric pressure and the
1628     * pressure at sea level.
1629     * <p>
1630     * Typically the atmospheric pressure is read from a
1631     * {@link Sensor#TYPE_PRESSURE} sensor. The pressure at sea level must be
1632     * known, usually it can be retrieved from airport databases in the
1633     * vicinity. If unknown, you can use {@link #PRESSURE_STANDARD_ATMOSPHERE}
1634     * as an approximation, but absolute altitudes won't be accurate.
1635     * </p>
1636     * <p>
1637     * To calculate altitude differences, you must calculate the difference
1638     * between the altitudes at both points. If you don't know the altitude
1639     * as sea level, you can use {@link #PRESSURE_STANDARD_ATMOSPHERE} instead,
1640     * which will give good results considering the range of pressure typically
1641     * involved.
1642     * </p>
1643     * <p>
1644     * <code><ul>
1645     *  float altitude_difference =
1646     *      getAltitude(SensorManager.PRESSURE_STANDARD_ATMOSPHERE, pressure_at_point2)
1647     *      - getAltitude(SensorManager.PRESSURE_STANDARD_ATMOSPHERE, pressure_at_point1);
1648     * </ul></code>
1649     * </p>
1650     *
1651     * @param p0 pressure at sea level
1652     * @param p atmospheric pressure
1653     * @return Altitude in meters
1654     */
1655   public static float getAltitude(float p0, float p) {
1656        final float coef = 1.0f / 5.255f;
1657        return 44330.0f * (1.0f - (float)Math.pow(p/p0, coef));
1658    }
1659
1660
1661   /**
1662     * {@hide}
1663     */
1664    public void onRotationChanged(int rotation) {
1665        synchronized(sListeners) {
1666            sRotation  = rotation;
1667        }
1668    }
1669
1670    static int getRotation() {
1671        synchronized(sListeners) {
1672            return sRotation;
1673        }
1674    }
1675
1676    private class LegacyListener implements SensorEventListener {
1677        private float mValues[] = new float[6];
1678        @SuppressWarnings("deprecation")
1679        private SensorListener mTarget;
1680        private int mSensors;
1681        private final LmsFilter mYawfilter = new LmsFilter();
1682
1683        @SuppressWarnings("deprecation")
1684        LegacyListener(SensorListener target) {
1685            mTarget = target;
1686            mSensors = 0;
1687        }
1688
1689        void registerSensor(int legacyType) {
1690            mSensors |= legacyType;
1691        }
1692
1693        boolean unregisterSensor(int legacyType) {
1694            mSensors &= ~legacyType;
1695            int mask = SENSOR_ORIENTATION|SENSOR_ORIENTATION_RAW;
1696            if (((legacyType&mask)!=0) && ((mSensors&mask)!=0)) {
1697                return false;
1698            }
1699            return true;
1700        }
1701
1702        @SuppressWarnings("deprecation")
1703        public void onAccuracyChanged(Sensor sensor, int accuracy) {
1704            try {
1705                mTarget.onAccuracyChanged(sensor.getLegacyType(), accuracy);
1706            } catch (AbstractMethodError e) {
1707                // old app that doesn't implement this method
1708                // just ignore it.
1709            }
1710        }
1711
1712        @SuppressWarnings("deprecation")
1713        public void onSensorChanged(SensorEvent event) {
1714            final float v[] = mValues;
1715            v[0] = event.values[0];
1716            v[1] = event.values[1];
1717            v[2] = event.values[2];
1718            int legacyType = event.sensor.getLegacyType();
1719            mapSensorDataToWindow(legacyType, v, SensorManager.getRotation());
1720            if (event.sensor.getType() == Sensor.TYPE_ORIENTATION) {
1721                if ((mSensors & SENSOR_ORIENTATION_RAW)!=0) {
1722                    mTarget.onSensorChanged(SENSOR_ORIENTATION_RAW, v);
1723                }
1724                if ((mSensors & SENSOR_ORIENTATION)!=0) {
1725                    v[0] = mYawfilter.filter(event.timestamp, v[0]);
1726                    mTarget.onSensorChanged(SENSOR_ORIENTATION, v);
1727                }
1728            } else {
1729                mTarget.onSensorChanged(legacyType, v);
1730            }
1731        }
1732
1733        /*
1734         * Helper function to convert the specified sensor's data to the windows's
1735         * coordinate space from the device's coordinate space.
1736         *
1737         * output: 3,4,5: values in the old API format
1738         *         0,1,2: transformed values in the old API format
1739         *
1740         */
1741        private void mapSensorDataToWindow(int sensor,
1742                float[] values, int orientation) {
1743            float x = values[0];
1744            float y = values[1];
1745            float z = values[2];
1746
1747            switch (sensor) {
1748                case SensorManager.SENSOR_ORIENTATION:
1749                case SensorManager.SENSOR_ORIENTATION_RAW:
1750                    z = -z;
1751                    break;
1752                case SensorManager.SENSOR_ACCELEROMETER:
1753                    x = -x;
1754                    y = -y;
1755                    z = -z;
1756                    break;
1757                case SensorManager.SENSOR_MAGNETIC_FIELD:
1758                    x = -x;
1759                    y = -y;
1760                    break;
1761            }
1762            values[0] = x;
1763            values[1] = y;
1764            values[2] = z;
1765            values[3] = x;
1766            values[4] = y;
1767            values[5] = z;
1768
1769            if ((orientation & Surface.ROTATION_90) != 0) {
1770                // handles 90 and 270 rotation
1771                switch (sensor) {
1772                    case SENSOR_ACCELEROMETER:
1773                    case SENSOR_MAGNETIC_FIELD:
1774                        values[0] =-y;
1775                        values[1] = x;
1776                        values[2] = z;
1777                        break;
1778                    case SENSOR_ORIENTATION:
1779                    case SENSOR_ORIENTATION_RAW:
1780                        values[0] = x + ((x < 270) ? 90 : -270);
1781                        values[1] = z;
1782                        values[2] = y;
1783                        break;
1784                }
1785            }
1786            if ((orientation & Surface.ROTATION_180) != 0) {
1787                x = values[0];
1788                y = values[1];
1789                z = values[2];
1790                // handles 180 (flip) and 270 (flip + 90) rotation
1791                switch (sensor) {
1792                    case SENSOR_ACCELEROMETER:
1793                    case SENSOR_MAGNETIC_FIELD:
1794                        values[0] =-x;
1795                        values[1] =-y;
1796                        values[2] = z;
1797                        break;
1798                    case SENSOR_ORIENTATION:
1799                    case SENSOR_ORIENTATION_RAW:
1800                        values[0] = (x >= 180) ? (x - 180) : (x + 180);
1801                        values[1] =-y;
1802                        values[2] =-z;
1803                        break;
1804                }
1805            }
1806        }
1807    }
1808
1809    class LmsFilter {
1810        private static final int SENSORS_RATE_MS = 20;
1811        private static final int COUNT = 12;
1812        private static final float PREDICTION_RATIO = 1.0f/3.0f;
1813        private static final float PREDICTION_TIME = (SENSORS_RATE_MS*COUNT/1000.0f)*PREDICTION_RATIO;
1814        private float mV[] = new float[COUNT*2];
1815        private float mT[] = new float[COUNT*2];
1816        private int mIndex;
1817
1818        public LmsFilter() {
1819            mIndex = COUNT;
1820        }
1821
1822        public float filter(long time, float in) {
1823            float v = in;
1824            final float ns = 1.0f / 1000000000.0f;
1825            final float t = time*ns;
1826            float v1 = mV[mIndex];
1827            if ((v-v1) > 180) {
1828                v -= 360;
1829            } else if ((v1-v) > 180) {
1830                v += 360;
1831            }
1832            /* Manage the circular buffer, we write the data twice spaced
1833             * by COUNT values, so that we don't have to copy the array
1834             * when it's full
1835             */
1836            mIndex++;
1837            if (mIndex >= COUNT*2)
1838                mIndex = COUNT;
1839            mV[mIndex] = v;
1840            mT[mIndex] = t;
1841            mV[mIndex-COUNT] = v;
1842            mT[mIndex-COUNT] = t;
1843
1844            float A, B, C, D, E;
1845            float a, b;
1846            int i;
1847
1848            A = B = C = D = E = 0;
1849            for (i=0 ; i<COUNT-1 ; i++) {
1850                final int j = mIndex - 1 - i;
1851                final float Z = mV[j];
1852                final float T = 0.5f*(mT[j] + mT[j+1]) - t;
1853                float dT = mT[j] - mT[j+1];
1854                dT *= dT;
1855                A += Z*dT;
1856                B += T*(T*dT);
1857                C +=   (T*dT);
1858                D += Z*(T*dT);
1859                E += dT;
1860            }
1861            b = (A*B + C*D) / (E*B + C*C);
1862            a = (E*b - A) / C;
1863            float f = b + PREDICTION_TIME*a;
1864
1865            // Normalize
1866            f *= (1.0f / 360.0f);
1867            if (((f>=0)?f:-f) >= 0.5f)
1868                f = f - (float)Math.ceil(f + 0.5f) + 1.0f;
1869            if (f < 0)
1870                f += 1.0f;
1871            f *= 360.0f;
1872            return f;
1873        }
1874    }
1875
1876
1877    /** Helper function to compute the angle change between two rotation matrices.
1878     *  Given a current rotation matrix (R) and a previous rotation matrix
1879     *  (prevR) computes the rotation around the x,y, and z axes which
1880     *  transforms prevR to R.
1881     *  outputs a 3 element vector containing the x,y, and z angle
1882     *  change at indexes 0, 1, and 2 respectively.
1883     * <p> Each input matrix is either as a 3x3 or 4x4 row-major matrix
1884     * depending on the length of the passed array:
1885     * <p>If the array length is 9, then the array elements represent this matrix
1886     * <pre>
1887     *   /  R[ 0]   R[ 1]   R[ 2]   \
1888     *   |  R[ 3]   R[ 4]   R[ 5]   |
1889     *   \  R[ 6]   R[ 7]   R[ 8]   /
1890     *</pre>
1891     * <p>If the array length is 16, then the array elements represent this matrix
1892     * <pre>
1893     *   /  R[ 0]   R[ 1]   R[ 2]   R[ 3]  \
1894     *   |  R[ 4]   R[ 5]   R[ 6]   R[ 7]  |
1895     *   |  R[ 8]   R[ 9]   R[10]   R[11]  |
1896     *   \  R[12]   R[13]   R[14]   R[15]  /
1897     *</pre>
1898     * @param R current rotation matrix
1899     * @param prevR previous rotation matrix
1900     * @param angleChange an array of floats in which the angle change is stored
1901     */
1902
1903    public static void getAngleChange( float[] angleChange, float[] R, float[] prevR) {
1904        float rd1=0,rd4=0, rd6=0,rd7=0, rd8=0;
1905        float ri0=0,ri1=0,ri2=0,ri3=0,ri4=0,ri5=0,ri6=0,ri7=0,ri8=0;
1906        float pri0=0, pri1=0, pri2=0, pri3=0, pri4=0, pri5=0, pri6=0, pri7=0, pri8=0;
1907        int i, j, k;
1908
1909        if(R.length == 9) {
1910            ri0 = R[0];
1911            ri1 = R[1];
1912            ri2 = R[2];
1913            ri3 = R[3];
1914            ri4 = R[4];
1915            ri5 = R[5];
1916            ri6 = R[6];
1917            ri7 = R[7];
1918            ri8 = R[8];
1919        } else if(R.length == 16) {
1920            ri0 = R[0];
1921            ri1 = R[1];
1922            ri2 = R[2];
1923            ri3 = R[4];
1924            ri4 = R[5];
1925            ri5 = R[6];
1926            ri6 = R[8];
1927            ri7 = R[9];
1928            ri8 = R[10];
1929        }
1930
1931        if(prevR.length == 9) {
1932            pri0 = prevR[0];
1933            pri1 = prevR[1];
1934            pri2 = prevR[2];
1935            pri3 = prevR[3];
1936            pri4 = prevR[4];
1937            pri5 = prevR[5];
1938            pri6 = prevR[6];
1939            pri7 = prevR[7];
1940            pri8 = prevR[8];
1941        } else if(prevR.length == 16) {
1942            pri0 = prevR[0];
1943            pri1 = prevR[1];
1944            pri2 = prevR[2];
1945            pri3 = prevR[4];
1946            pri4 = prevR[5];
1947            pri5 = prevR[6];
1948            pri6 = prevR[8];
1949            pri7 = prevR[9];
1950            pri8 = prevR[10];
1951        }
1952
1953        // calculate the parts of the rotation difference matrix we need
1954        // rd[i][j] = pri[0][i] * ri[0][j] + pri[1][i] * ri[1][j] + pri[2][i] * ri[2][j];
1955
1956        rd1 = pri0 * ri1 + pri3 * ri4 + pri6 * ri7; //rd[0][1]
1957        rd4 = pri1 * ri1 + pri4 * ri4 + pri7 * ri7; //rd[1][1]
1958        rd6 = pri2 * ri0 + pri5 * ri3 + pri8 * ri6; //rd[2][0]
1959        rd7 = pri2 * ri1 + pri5 * ri4 + pri8 * ri7; //rd[2][1]
1960        rd8 = pri2 * ri2 + pri5 * ri5 + pri8 * ri8; //rd[2][2]
1961
1962        angleChange[0] = (float)Math.atan2(rd1, rd4);
1963        angleChange[1] = (float)Math.asin(-rd7);
1964        angleChange[2] = (float)Math.atan2(-rd6, rd8);
1965
1966    }
1967
1968    /** Helper function to convert a rotation vector to a rotation matrix.
1969     *  Given a rotation vector (presumably from a ROTATION_VECTOR sensor), returns a
1970     *  9  or 16 element rotation matrix in the array R.  R must have length 9 or 16.
1971     *  If R.length == 9, the following matrix is returned:
1972     * <pre>
1973     *   /  R[ 0]   R[ 1]   R[ 2]   \
1974     *   |  R[ 3]   R[ 4]   R[ 5]   |
1975     *   \  R[ 6]   R[ 7]   R[ 8]   /
1976     *</pre>
1977     * If R.length == 16, the following matrix is returned:
1978     * <pre>
1979     *   /  R[ 0]   R[ 1]   R[ 2]   0  \
1980     *   |  R[ 4]   R[ 5]   R[ 6]   0  |
1981     *   |  R[ 8]   R[ 9]   R[10]   0  |
1982     *   \  0       0       0       1  /
1983     *</pre>
1984     *  @param rotationVector the rotation vector to convert
1985     *  @param R an array of floats in which to store the rotation matrix
1986     */
1987    public static void getRotationMatrixFromVector(float[] R, float[] rotationVector) {
1988
1989        float q0;
1990        float q1 = rotationVector[0];
1991        float q2 = rotationVector[1];
1992        float q3 = rotationVector[2];
1993
1994        if (rotationVector.length == 4) {
1995            q0 = rotationVector[3];
1996        } else {
1997            q0 = 1 - q1*q1 - q2*q2 - q3*q3;
1998            q0 = (q0 > 0) ? (float)Math.sqrt(q0) : 0;
1999        }
2000
2001        float sq_q1 = 2 * q1 * q1;
2002        float sq_q2 = 2 * q2 * q2;
2003        float sq_q3 = 2 * q3 * q3;
2004        float q1_q2 = 2 * q1 * q2;
2005        float q3_q0 = 2 * q3 * q0;
2006        float q1_q3 = 2 * q1 * q3;
2007        float q2_q0 = 2 * q2 * q0;
2008        float q2_q3 = 2 * q2 * q3;
2009        float q1_q0 = 2 * q1 * q0;
2010
2011        if(R.length == 9) {
2012            R[0] = 1 - sq_q2 - sq_q3;
2013            R[1] = q1_q2 - q3_q0;
2014            R[2] = q1_q3 + q2_q0;
2015
2016            R[3] = q1_q2 + q3_q0;
2017            R[4] = 1 - sq_q1 - sq_q3;
2018            R[5] = q2_q3 - q1_q0;
2019
2020            R[6] = q1_q3 - q2_q0;
2021            R[7] = q2_q3 + q1_q0;
2022            R[8] = 1 - sq_q1 - sq_q2;
2023        } else if (R.length == 16) {
2024            R[0] = 1 - sq_q2 - sq_q3;
2025            R[1] = q1_q2 - q3_q0;
2026            R[2] = q1_q3 + q2_q0;
2027            R[3] = 0.0f;
2028
2029            R[4] = q1_q2 + q3_q0;
2030            R[5] = 1 - sq_q1 - sq_q3;
2031            R[6] = q2_q3 - q1_q0;
2032            R[7] = 0.0f;
2033
2034            R[8] = q1_q3 - q2_q0;
2035            R[9] = q2_q3 + q1_q0;
2036            R[10] = 1 - sq_q1 - sq_q2;
2037            R[11] = 0.0f;
2038
2039            R[12] = R[13] = R[14] = 0.0f;
2040            R[15] = 1.0f;
2041        }
2042    }
2043
2044    /** Helper function to convert a rotation vector to a normalized quaternion.
2045     *  Given a rotation vector (presumably from a ROTATION_VECTOR sensor), returns a normalized
2046     *  quaternion in the array Q.  The quaternion is stored as [w, x, y, z]
2047     *  @param rv the rotation vector to convert
2048     *  @param Q an array of floats in which to store the computed quaternion
2049     */
2050    public static void getQuaternionFromVector(float[] Q, float[] rv) {
2051        if (rv.length == 4) {
2052            Q[0] = rv[3];
2053        } else {
2054            Q[0] = 1 - rv[0]*rv[0] - rv[1]*rv[1] - rv[2]*rv[2];
2055            Q[0] = (Q[0] > 0) ? (float)Math.sqrt(Q[0]) : 0;
2056        }
2057        Q[1] = rv[0];
2058        Q[2] = rv[1];
2059        Q[3] = rv[2];
2060    }
2061
2062    private static native void nativeClassInit();
2063
2064    private static native int sensors_module_init();
2065    private static native int sensors_module_get_next_sensor(Sensor sensor, int next);
2066
2067    // Used within this module from outside SensorManager, don't make private
2068    static native int sensors_create_queue();
2069    static native void sensors_destroy_queue(int queue);
2070    static native boolean sensors_enable_sensor(int queue, String name, int sensor, int enable);
2071    static native int sensors_data_poll(int queue, float[] values, int[] status, long[] timestamp);
2072}
2073